[PATCH 02/17] spi: spi-geni-qcom: Fix use-after-free on unbind

[Lukas Wunner <lukas@wunner.de>]

spi_geni_remove() accesses the driver's private data after calling
spi_unregister_master() even though that function releases the last
reference on the spi_master and thereby frees the private data.

Moreover, since commit 1a9e489e6128 ("spi: spi-geni-qcom: Use OPP API to
set clk/perf state"), spi_geni_probe() leaks the spi_master allocation
if the calls to dev_pm_opp_set_clkname() or dev_pm_opp_of_add_table()
fail.

Fix by switching over to the new devm_spi_alloc_master() helper which
keeps the private data accessible until the driver has unbound and also
avoids the spi_master leak on probe.

Fixes: 561de45f72bd ("spi: spi-geni-qcom: Add SPI driver support for GENI based QUP")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: <stable@vger.kernel.org> # v4.20+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc: <stable@vger.kernel.org> # v4.20+
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Cc: Girish Mahadevan <girishm@codeaurora.org>
---
 drivers/spi/spi-geni-qcom.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
index 25810a7eef10..0e3d8e6c08f4 100644
--- a/drivers/spi/spi-geni-qcom.c
+++ b/drivers/spi/spi-geni-qcom.c
@@ -603,7 +603,7 @@ static int spi_geni_probe(struct platform_device *pdev)
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);
 
-	spi = spi_alloc_master(dev, sizeof(*mas));
+	spi = devm_spi_alloc_master(dev, sizeof(*mas));
 	if (!spi)
 		return -ENOMEM;
 
@@ -673,7 +673,6 @@ static int spi_geni_probe(struct platform_device *pdev)
 	free_irq(mas->irq, spi);
 spi_geni_probe_runtime_disable:
 	pm_runtime_disable(dev);
-	spi_master_put(spi);
 	dev_pm_opp_of_remove_table(&pdev->dev);
 put_clkname:
 	dev_pm_opp_put_clkname(mas->se.opp_table);
-- 
2.29.2